KR20130098606A - Food container having improved oxygen barrier properties and the manufacturing method thereof - Google Patents

Abstract

PURPOSE: A method of manufacturing a food container by depositing an oxygen barrier on a plastic container by using a plasma method is provided. CONSTITUTION: A buffer film (20) is formed on a surface of a plastic container and has a thickness of 5 nm to 30 nm. An oxygen barrier (30) is formed on the buffer film. A food container (1) has oxygen barrier properties. The oxygen barrier has a thickness of 25 nm to 50 nm. A surface of the container is plasma pre-treated for improving an adhesion power to the buffer film. The container is formed of polypropylene. The buffer film is formed of hexamethyldisiloxane or silicon. An oxygen barrier is formed of a silicon oxide.

Description

FOOD CONTAINER HAVING IMPROVED OXYGEN BARRIER PROPERTIES AND THE MANUFACTURING METHOD THEREOF

The present invention relates to a food container and a method for manufacturing the same, and more particularly, food that can greatly increase oxygen barrier properties by depositing an oxygen barrier thin film without plasma by a plasma method in a container having a low surface energy and a porous plastic material. A container and a method of manufacturing the same.

In order to store perishable foods for a long time, it is very important to make food containers have oxygen blocking ability.

Food containers made of plastics have great advantages such as low price and ease of mass production, but have a disadvantage in that the oxygen barrier property is significantly lowered due to the porous structure characteristic of plastics.

In order to solve this problem, a technique of coating a thin film on a plastic food container using a plasma method has been studied.

However, the results of these studies are limited to plastics with relatively high surface energy (0.031 ~ 0.047 N / m, Accu dyne test) such as polyethylene terephthalate (PET), and surface such as polypropylene (PP). It has no effect on plastics with low energy (0.023 ~ 0.038 N / m, Accu dyne test).

This is known to be due to the characteristic of polypropylene (PP), which is more porous than polyethylene terephthalate (PET). (N. Inagaki, et al., Journal of Applied Polymer Science 78 (2000) 2389-2397.)

As a result, in polyethylene terephthalate (PET), the oxygen barrier property increases as the thickness of the thin film deposited on the surface increases, whereas in polypropylene (PP), oxygen is increased even if the thickness of the thin film deposited on the surface is increased. It shows no blocking. [Reference: D.S. Finch, et al., Packaging Technology and Science 9 (1996) 73-85.]

This means that the thin film deposited on the surface of the polypropylene (PP) is difficult to adhere to the surface of the polypropylene (PP) due to the low surface energy and the porous structure of the polypropylene (PP), and thus peels off or breaks.

For this reason, a product that adds oxygen barrier property by coating a thin film on polypropylene (PP) by a plasma method could not be obtained. However, polypropylene (PP) has advantages such as price competitiveness, heat resistance, and stability against environmental hormones compared to other plastic materials such as polyethylene terephthalate (PET), and when applied to food containers with improved oxygen barrier properties The material is expected to have great economic value.

An object of the present invention devised to solve the above problems is a food container which can greatly increase the oxygen barrier property by depositing the oxygen barrier thin film in a plastic container of low surface energy and porous material without a break through the plasma method. It is to provide a manufacturing method.

According to a feature of the present invention for achieving the object as described above, the food container having an improved oxygen barrier property of the present invention is formed on the surface of the container of the plastic material, the container, having a thickness of 5nm to 30nm And a buffer thin film and an oxygen barrier thin film formed on the buffer thin film.

In addition, the oxygen barrier thin film is characterized in that the thickness of 25nm to 50nm.

In addition, the surface of the container is characterized in that the plasma pre-treatment, in order to improve the adhesion with the buffer thin film.

In addition, the container is characterized in that formed of polypropylene (PP).

In addition, the buffer thin film is characterized in that formed of hexamethyldisiloxane (HMDSO) or silicon (Si).

In addition, the oxygen barrier thin film is characterized in that formed of silicon oxide (silicon oxide).

The apparatus may further include a functional thin film formed on the oxygen barrier thin film.

In addition, the functional thin film is characterized in that formed of hexamethyldisiloxane (HMDSO) or F-DLC (Fluorine incorporated Diamond Like Carbon).

The method for producing a food container having an improved oxygen barrier property of the present invention comprises the steps of: (a) preparing a container made of plastic, (b) treating the surface of the container with oxygen plasma, and (c) on the surface of the container. Depositing and forming a buffer thin film having a thickness of 5 nm to 30 nm in the (d) depositing and forming an oxygen barrier thin film on the buffer thin film.

In addition, the oxygen barrier thin film is characterized in that the thickness of 25nm to 50nm.

In addition, the container is characterized in that formed of polypropylene (PP).

In addition, the step (c) and the step (d) is characterized in that the progress through the plasma chemical vapor deposition (Plasma Chemical Vapor Deposition).

In addition, the buffer thin film is characterized in that formed of hexamethyldisiloxane (HMDSO) or silicon (Si).

In addition, the oxygen barrier thin film is characterized in that formed of silicon oxide (silicon oxide).

In addition, (e) further comprising depositing and forming a functional thin film on the oxygen barrier thin film.

In addition, the functional thin film is characterized in that formed of hexamethyldisiloxane (HMDSO) or F-DLC (Fluorine incorporated Diamond Like Carbon).

According to the present invention as described above, by depositing the oxygen barrier thin film in a plastic container having a low surface energy and porous material without plasma, it is possible to provide a food container and a manufacturing method thereof that can greatly increase the oxygen barrier properties. Can be.

1 is a view showing a food container according to a first embodiment of the present invention.
2 is a view showing a manufacturing method of the food container shown in FIG.
3 is a graph comparing oxygen barrier properties of a specimen not subjected to plasma pretreatment and a specimen subjected to plasma pretreatment.
4 is a graph showing oxygen barrier properties that change as the thicknesses of the buffer thin film and the oxygen barrier thin film are changed.
FIG. 5 is a view showing an image of the surface shape of a food container which is changed while increasing the thickness of the buffer thin film using a scanning electron microscope (SEM) for the case where the thickness of the oxygen barrier thin film is 30 nm. .
6 is a view showing a food container according to a second embodiment of the present invention.
7 is a view showing a manufacturing method of the food container shown in FIG.

The details of other embodiments are included in the detailed description and drawings.

Advantages and features of the present invention and methods for achieving them will be apparent with reference to the embodiments described below in detail with the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. To fully disclose the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims. Like reference numerals refer to like elements throughout.

Hereinafter, with reference to the embodiments of the present invention and the drawings for explaining the same will be described for the food container having the improved oxygen barrier properties and the manufacturing method thereof.

1 is a view showing a food container according to a first embodiment of the present invention.

1, the food container (1, hereinafter referred to as "food container") having an improved oxygen barrier property according to the first embodiment of the present invention is a container 10, buffer thin film 20, oxygen blocking thin film ( 30).

The container 10 may have a predetermined accommodation space in which food is contained, and is formed of a plastic material.

It is in accordance with the spirit of the present invention that the container 10 is formed of a material such as polypropylene (PP), which has a low surface energy and is porous, but has a lower or porous surface energy than polypropylene (PP). It may be formed of a plastic material, and may be formed of a plastic material having a high surface energy such as polyethylene terephthalate (PET).

The buffer thin film 20 is formed on the surface 12 of the container 10, and preferably has a thickness of 5 nm to 30 nm in order to realize optimal oxygen barrier properties.

The buffer thin film 20 is preferably formed of hexamethyldisiloxane (HMDSO), but may also be formed of silicon (Si).

At this time, it is preferable that the surface 12 of the container 10 in which the buffer thin film 20 is formed is plasma pretreated before formation of the buffer thin film 20 in order to improve adhesion to the buffer thin film 20.

Oxygen barrier thin film 30 is formed on the buffer thin film 20, it is preferable to have a thickness of 25nm to 50nm in order to implement the optimum oxygen barrier properties.

In addition, the oxygen barrier thin film 30 is preferably formed of silicon oxide (SiOx).

2 is a view showing a manufacturing method of the food container shown in FIG.

Referring to Figure 2, the manufacturing method of the food container 1 according to the first embodiment of the present invention is a container preparation step (S100), plasma pretreatment step (S200), buffer thin film deposition step (S300), oxygen barrier thin film deposition Step S400 is included.

In the container preparation step (S100) to prepare a container 10 of plastic material.

At this time, it is preferable that the container 10 is formed of polypropylene (PP) having low surface energy, large porous properties, and difficult to attach a thin film.

In the plasma pretreatment step (S200), the surface 12 of the container 10 is oxygen plasma treated to increase the surface energy of the container 10 before the buffer thin film 20 is deposited.

Specifically, referring to the plasma pretreatment step (S200), first, the vessel 10 made of polypropylene (PP) is placed in a chamber of a Radio Frequency-Chemical Vapor Deposition (RF-CVD) device (not shown), and a pump is used. It builds up a vacuum in the chamber.

Thereafter, oxygen gas is introduced into the chamber at a constant flow rate, and the plasma pretreatment process is performed by applying RF-power to generate a plasma state.

As the plasma state is formed, a self-bias voltage occurs in the chamber, whereby the oxygen particles react with the surface 12 of the vessel 10 with energy.

The surface energy of the container 10 is increased by the chemical reaction of oxygen and the container surface 12.

Therefore, the adhesion between the buffer thin film 20 and the container 10 to be formed in the buffer thin film deposition step S300 later may be increased, and the oxygen barrier property may also be increased.

Refer to FIG. 3 comparing the oxygen barrier properties of the specimen (HMDSO (100 nm) / SiOx (50 nm)) without the plasma pretreatment and the specimen (O ₂ / HMDSO (100 nm) / SiOx (50 nm)) without the plasma pretreatment. In other words, it can be seen that the oxygen barrier property of the specimen subjected to plasma pretreatment is higher than that of the other specimen. (Oxygen Transmission Rate (OTR) of the specimen subjected to plasma pretreatment is lower than that of the other specimen)

This is because, if the plasma surface pretreatment is not performed on the container surface 12, since the subsequent thin films are not deposited well, the quality of the thin films is poor and the oxygen barrier property is inferior.

In the buffer thin film deposition step (S300), the buffer thin film 20 is deposited on the surface 12 of the plasma-treated container 10.

The buffer thin film 20 serves to absorb the mechanical deformation of the plastic container 10 without transferring it directly to the oxygen barrier thin film 30 to be deposited on the buffer thin film 20.

The buffer thin film 20 is a thin film having a relatively low Young's modulus and is relatively deformed, and may be formed of materials such as hexamethyldisiloxane (HMDSO) or silicon (Si).

Specifically, referring to the buffer thin film deposition step (S300), after the plasma pretreatment step (S200), hexamethyldisiloxane (HMDSO) gas is introduced into the chamber of the RF-CVD apparatus to form a plasma state.

By the plasma reaction of hexamethyldisiloxane (HMDSO) gas, a buffer thin film 20 made of plasma polymerized HMDSO (pp-HMDSO) is formed on the surface 12 of the container 10. Can be.

FIG. 4 is a graph showing oxygen barrier properties as the thicknesses of the buffer thin film and the oxygen barrier thin film change, and the 'optimum thickness' of the buffer thin film 20 and the oxygen barrier thin film 30 for obtaining excellent oxygen barrier properties. Indicates the presence of.

In particular, the graph of FIG. 4 shows the results of experiments by forming a plasma polymerized hexamethyldisiloxane (pp-HMDSO) buffer thin film 20 and a silicon oxide (SiOx) oxygen blocking thin film 30.

4, the buffer thin film 20 of the present invention preferably has a thickness of 5nm to 30nm.

When the buffer thin film 20 is formed to be too thin, the buffer role is not sufficiently digested, and when the buffer thin film 20 is formed to be too thick, the oxygen barrier thin film 30 by the compression energy of the buffer thin film 20 This is because the breakage of the oxygen blocking property may be inhibited.

In addition, when the buffer thin film 20 is formed to a thickness of 5nm to 30nm as shown in Figure 4, it can be seen that it has excellent oxygen barrier properties compared to the other thickness.

Particularly, when the oxygen barrier thin film 30 made of silicon oxide (SiOx) is formed with a thickness of 30 nm, if the buffer thin film 20 is formed with a thickness of about 8 nm to 10 nm, it has a significantly low oxygen permeability of 0.03 cc / pkg. High oxygen barrier properties can be realized.

In addition, even when the oxygen barrier thin film 30 made of silicon oxide (SiOx) is formed to a thickness of 50 nm, if the buffer thin film 20 is formed to a thickness of about 8 nm to 10 nm, it has a low oxygen permeability of 0.07 cc / pkg. High oxygen barrier properties can be realized.

FIG. 5 is a view showing an image of the surface shape of a food container which is changed while increasing the thickness of the buffer thin film using a scanning electron microscope (SEM) for the case where the thickness of the oxygen barrier thin film is 30 nm. .

In addition, referring to FIG. 5, when the buffer thin film 20 made of plasma-polymerized hexamethyldisiloxane (pp-HMDSO) is 8 nm to 10 nm, the crack of the oxygen barrier thin film 30 is minimized to provide the best oxygen barrier property. In the case where the thickness of the buffer thin film 20 was increased to 30 nm, a slight crack occurred in the oxygen barrier thin film 30, and the oxygen barrier property was slightly decreased.

However, when the thickness of the buffer thin film 20 was increased to 50 nm, the oxygen barrier thin film 30 was severely cracked due to the compressive energy of the buffer thin film 20, and thus, the oxygen barrier property rapidly decreased. .

In the oxygen barrier thin film deposition step (S400), an oxygen barrier thin film 30 is deposited on the buffer thin film 20.

The oxygen barrier thin film 30 is a thin film having a high density and serves to prevent oxygen molecules from entering and exiting the food container 1.

Generally, on the plastic material such as polyethylene terephthalate (PET), it is known that the oxygen barrier property is improved as the thickness of the oxygen barrier thin film 30 increases, but not on the material such as polypropylene (PP).

The reason is that when the oxygen barrier thin film 30 is deposited too thick on the polypropylene (PP), adhesion is not excellent and cracking occurs.

In addition, in the case where the oxygen barrier thin film 30 is formed to be too thin, sufficient oxygen barrier properties may not be realized.

In order to satisfy the above conditions, as shown in FIG. 4, it is preferable to set the thickness of the oxygen barrier thin film 30 to 25 nm to 50 nm.

That is, when the thickness of the oxygen barrier thin film 30 is set to 25 nm to 50 nm, an oxygen transmittance of 0.1 cc / pkg or less can be achieved. Oxygen permeability of 0.1 cc / pkg or less is 10 times reduced compared to the oxygen permeability of polypropylene (PP) itself, and exhibits an oxygen barrier property that can allow long-term storage of food contained in the container 10 sufficiently. .

In particular, as shown in FIG. 4, in order to achieve the lowest oxygen permeability, the thickness of the oxygen barrier thin film 30 may be set to about 30 nm, preferably 25 nm to 35 nm.

Silicon oxide (SiOx) is preferable as a material that can be used for the oxygen barrier thin film 30.

Specifically, the oxygen barrier thin film deposition step (S400), after the buffer thin film deposition step (S300) proceeds a small amount of oxygen gas and a large amount of hexamethyldisiloxane (HMDSO) gas in the chamber of the RF-CVD equipment, plasma reaction By proceeding to form an oxygen barrier thin film 30 of the silicon oxide (SiOx) material on the buffer thin film (20).

Conventionally, a method of increasing oxygen barrier property by mixing or bonding expensive ethylene vinyl alcohol (EVOH) to polypropylene (PP) is used. However, the present invention does not use ethylene vinyl alcohol (EVOH). As a result, cost can be reduced and price competitiveness can be achieved.

In addition, in the method using ethylene vinyl alcohol (EVOH), it is difficult to recycle because a large amount of materials other than polypropylene (PP) is contained in the food container, but the present invention using the plasma method has the advantage of easy recycling.

6 is a view showing a food container according to a second embodiment of the present invention.

Referring to FIG. 6, the food container 1 ′ according to the second embodiment of the present invention further includes a functional thin film 40 as compared to the food container 1 according to the first embodiment of the present invention.

The functional thin film 40 is to add desired surface properties on the oxygen barrier thin film 30 and may be formed on the oxygen barrier thin film 30.

Here, the functional thin film 40 may have surface properties such as hydrophobicity, low friction characteristics, and the like, and the functional thin film 40 also includes compressive energy, and thus, is preferably formed to an optimal thickness.

As the hydrophobic functional thin film 40, hexamethyldisiloxane (HMDSO) or Fluorine incorporated Diamond Like Carbon (F-DLC) having low surface energy may be used.

7 is a view showing a manufacturing method of the food container shown in FIG.

Referring to FIG. 7, the method for manufacturing the food container 1 ′ according to the second embodiment of the present invention is a functional thin film deposition step (S500) compared to the method for manufacturing the food container 1 according to the first embodiment of the present invention. More).

The functional thin film deposition step (S500) is performed after the oxygen barrier thin film deposition step (S400), and in the functional thin film deposition step (S500), the functional thin film 40 is deposited on the oxygen barrier thin film 30.

The deposition formation of the functional thin film 40 may be performed by plasma chemical vapor deposition (Plasma CVD) similarly to the buffer thin film deposition step (S300) and the oxygen barrier thin film deposition step (S400).

Therefore, when hexamethyldisiloxane (HMDSO) gas is introduced into the chamber of the RF-CVD apparatus to form a plasma state, the functional thin film 40 made of plasma-polymerized hexamethyldisiloxane (pp-HMDSO) material is an oxygen barrier thin film. 30 can be formed on.

It will be understood by those skilled in the art that the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. The scope of the present invention is defined by the appended claims rather than the foregoing detailed description, and all changes or modifications derived from the meaning and scope of the claims and the equivalents thereof are included in the scope of the present invention Should be interpreted.

1, 1 ': food container
10: container 20: buffer thin film
30: oxygen blocking thin film 40: functional thin film

Claims (16)

Plastic containers;
A buffer thin film formed on the surface of the container and having a thickness of 5 nm to 30 nm; And
An oxygen barrier thin film formed on the buffer thin film; Food container having an improved oxygen barrier properties, including. The method of claim 2, wherein the oxygen barrier thin film,
Food container having improved oxygen barrier properties, characterized in that the thickness of 25nm to 50nm. The method of claim 1, wherein the surface of the container,
Food container having improved oxygen barrier properties, characterized in that the plasma pre-treatment, to improve the adhesion to the buffer thin film. The container according to claim 1,
Characterized in that it is formed of polypropylene (PP). The method of claim 1, wherein the buffer thin film,
Food container having improved oxygen barrier properties, characterized in that formed of hexamethyldisiloxane (HMDSO) or silicon (Si). The oxygen-barrier thin film according to claim 1,
Characterized in that it is formed of silicon oxide. The method of claim 1,
A functional thin film formed on the oxygen barrier thin film; Food container having an improved oxygen barrier properties further comprising. The method of claim 7, wherein the functional thin film,
Food container having improved oxygen barrier properties, characterized in that formed by hexamethyldisiloxane (HMDSO) or F-DLC (Fluorine incorporated Diamond Like Carbon). (a) preparing a plastic container;
(b) oxygen plasma treating the surface of the vessel;
(c) depositing a buffer thin film having a thickness of 5 nm to 30 nm on the surface of the container; And
(d) depositing an oxygen barrier thin film on the buffer thin film; Method of producing a food container having an improved oxygen barrier properties comprising a. The method of claim 9, wherein the oxygen barrier thin film,
A method for producing a food container having improved oxygen barrier properties, characterized in that the thickness of 25nm to 50nm. The method of claim 9, wherein the container,
Wherein the container is formed of polypropylene (PP). The method of claim 9, wherein step (c) and step (d)
A method for producing a food container having improved oxygen barrier properties, characterized in that it is carried out through plasma chemical vapor deposition (Plasma Chemical Vapor Deposition). The method of claim 9, wherein the buffer thin film,
A method for producing a food container having improved oxygen barrier properties, characterized in that formed from hexamethyldisiloxane (HMDSO) or silicon (Si). The method of claim 9, wherein the oxygen barrier thin film,
Wherein the food container is formed of silicon oxide. 10. The method of claim 9,
(e) depositing a functional thin film on the oxygen barrier thin film; Method of producing a food container having an improved oxygen barrier properties further comprising. The method of claim 16, wherein the functional thin film,
Method for producing a food container having improved oxygen barrier properties, characterized in that formed with hexamethyldisiloxane (HMDSO) or F-DLC (Fluorine incorporated Diamond Like Carbon).

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